executive summary:This article uses the case of Japanese security policy in the past decade to develop the Alliance-Enhancing Framework, which offers a way to understand the conditions in which security-dependent states can either trigger or escape their alliance dilemma with the U.S.main argument This article asks a question that is at the core of much of East Asia's security policy: how can a country that is dependent on the U.S. for its security enhance its policymaking options in ways that will not threaten its U.S. alliance but still provide avenues to develop its own leadership and broader security roles? The alliance dilemma is the possibility, on the one hand, of the weaker state being abandoned by its more powerful partner if it becomes too independent or powerful, among other reasons, and, on the other hand, of entrapment and alliance dependence if the weaker state does not strengthen itself. Through a careful examination of Japan's recent security policy, we develop the Alliance-Enhancing Framework to understand the conditions under which security-dependent states can transform their asymmetric alliances into ones that are more collaborative, with both sides making meaningful contributions to collective security. The framework reveals that alliance tension can be provoked by certain types of unilateral policy initiatives undertaken by the dependent ally, but that some unilateral, as well as bilateral, actions and regional initiatives generally enhance and improve the partnership.policy implications • If smaller allies like Japan pursue unilateral measures that disrupt or undermine their cornerstone alliance, they risk losing their alliance partner and potentially weakening their security standing in the region. However, security reforms that support both the ally's own national security and the alliance can be successful in knitting the partners closer together.• Beneficial security initiatives, such as co-development or co-production projects, can bolster a security-dependent ally's defense posture and simultaneously help transform an asymmetric bilateral alliance relationship into one that is more mutually dependent and reliant on shared capabilities.• Regional security initiatives linked to the U.S. alliance and its common values confer the biggest advantage for security-dependent countries like Japan. They allow the smaller country to exert geopolitical influence by extending the range and scope of ally-friendly networks alongside the U.S. while also exhibiting leadership and acting more independently.